Flexible tube for cartridge filter

ABSTRACT

Embolic protection filtering devices and methods of making and using the same. The present invention may include an embolic protection filtering device including a filter cartridge that is slidable over medical devices, for example, guidewires. The filter cartridge may have a filter coupled thereto and may have desirable flexibility and trackability characteristics.

FIELD OF THE INVENTION

[0001] The present invention pertains to embolic protection filters.More particularly, the present invention pertains to filters coupled toa shaft having desirable flexibility and trackability characteristics.

BACKGROUND

[0002] Heart and vascular disease are major problems in the UnitedStates and throughout the world. Conditions such as atherosclerosisresult in blood vessels becoming blocked or narrowed. This blockage canresult in lack of oxygenation of the heart, which has significantconsequences since the heart muscle must be well oxygenated in order tomaintain its blood pumping action.

[0003] Occluded, stenotic, or narrowed blood vessels may be treated witha number of relatively non-invasive medical procedures includingpercutaneous transluminal angioplasty (PTA), percutaneous transluminalcoronary angioplasty (PTCA), and atherectomy. Angioplasty techniquestypically involve the use of a balloon catheter. The balloon catheter isadvanced over a guidewire such that the balloon is positioned adjacent astenotic lesion. The balloon is then inflated and the restriction of thevessel is opened. During an atherectomy procedure, the stenotic lesionmay be mechanically cut away from the blood vessel wall using anatherectomy catheter.

[0004] During angioplasty and atherectomy procedures, embolic debris canbe separated from the wall of the blood vessel. If this debris entersthe circulatory system, it could block other vascular regions includingthe neural and pulmonary vasculature. During angioplasty procedures,stenotic debris may also break loose due to manipulation of the bloodvessel. Because of this debris, a number of devices, termed embolicprotection devices, have been developed to filter out this debris.

BRIEF SUMMARY

[0005] The present invention pertains to embolic protection filteringdevices. In at least some embodiments, the filtering device may includea filter cartridge having a filter coupled thereto. The filter cartridgemay be configured to be slidable over a medical device, for example aguidewire, and may have desirable flexibility, trackability, and otherfeatures and/or characteristics as described in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006]FIG. 1 is a perspective view of an example embolic protectionfiltering device;

[0007]FIG. 2 is a perspective view of another example filter cartridge;

[0008]FIG. 3 is a perspective view of another example filter cartridge;

[0009]FIG. 4 is a perspective view of another example filter cartridge;

[0010]FIG. 5 is a perspective view of another example filter cartridge;

[0011]FIG. 6 is a perspective view of an example mandrel;

[0012]FIG. 7 is a cross-sectional view-taken through line 7-7;

[0013]FIG. 8 is an alternative cross-sectional view taken through line7-7; and

[0014]FIG. 9 is a perspective view of another example mandrel.

DETAILED DESCRIPTION

[0015] The following description should be read with reference to thedrawings wherein like reference numerals indicate like elementsthroughout the several views. The detailed description and drawingsillustrate example embodiments of the claimed invention.

[0016]FIG. 1 illustrates an example embolic protection filtering device10. Device 10 may include a tubular filter cartridge 12 having a filter14 coupled thereto. Filter cartridge 12 may have desirable flexibility,trackability, and/or other characteristics that allow it to be exchangedover other medical devices such as a guidewire 16 (as shown in FIG. 1),a catheter, and the like. Moreover, because a number of the features andcharacteristics of filter cartridge 12 can be varied, cartridge 12 canbe configured to be slidable over essentially any medical device,including virtually all commercially available guidewires and catheters.

[0017] Filter cartridge 12 may be comprised of a number of differentmaterials including metals, metal alloys, polymers, or the like, orcombinations or mixtures thereof. For example, filter cartridge 12 maybe comprised of super elastic, linear elastic, and/or shape memorymetals and/or metal alloys. Some examples of suitable metals and metalalloys include stainless steel, such as 304v stainless steel; such asnickel-titanium alloy, such as nitinol, nickel-chromium alloy,nickel-chromium-iron alloy, cobalt alloy, titanium and/or titaniumalloys, or the like; or other suitable material.

[0018] Some examples of suitable polymers may includepolytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE),fluorinated ethylene propylene (FEP), polyurethane, polypropylene (PP),polyvinylchloride (PVC), polyether-ester (for example a polyether-esterelastomer such as ARNITEL® available from DSM Engineering Plastics),polyester (for example a polyester elastomer such as HYTREL® availablefrom DuPont), polyamide (for example, DURETHAN® available from Bayer orCRISTAMID® available from Elf Atochem), elastomeric polyamides, blockpolyamide/ethers, polyether block amide (PEBA, for example availableunder the trade name PEBAX®), silicones, polyethylene, Marlexhigh-density polyethylene, Marlex low-density polyethylene, linear lowdensity polyethylene (for example REXELL®), polyethylene terephthalate(PET), polyetheretherketone (PEEK), polyimide (PI), polyetherimide(PEI), polyphenylene sulfide (PPS), polyphenylene oxide (PPO),polysulfone, nylon, perfluoro(propyl vinyl ether) (PFA), other suitablematerials, or mixtures, combinations, or copolymers thereof. In someembodiments filter cartridge 12 can include a liquid crystal polymer(LCP) blended with other polymers to enhance torqueability. By employingselection of materials and processing techniques, thermoplastic, solventsoluble, and thermosetting variants of these and other materials can beemployed to achieve the desired results.

[0019] In some embodiments, a coating, for example a lubricious, ahydrophilic, a protective, or other type of coating may be applied overportions or all of filter cartridge 12, or other portions of device 10.Hydrophobic coatings such as fluoropolymers provide a dry lubricitywhich improves guidewire handling and device exchanges. Lubriciouscoatings improve steerability and improve lesion crossing capability.Suitable lubricious polymers are well known in the art and may includesilicone and the like, hydrophilic polymers such as polyarylene oxides,polyvinylpyrolidones, polyvinylalcohols, hydroxy alkyl cellulosics,algins, saccharides, caprolactones, and the like, and mixtures andcombinations thereof. Hydrophilic polymers may be blended amongthemselves or with formulated amounts of water insoluble compounds(including some polymers) to yield coatings with suitable lubricity,bonding, and solubility.

[0020] In some embodiments, filter cartridge 12 or portions thereof maybe doped with, plated with, or otherwise include a radiopaque material.Radiopaque materials are understood to be materials capable of producinga relatively bright image on a fluoroscopy screen or another imagingtechnique during a medical procedure. This relatively bright image aidsthe user of device 10 in determining its location. Some examples ofradiopaque materials can include, but are not limited to, gold,platinum, palladium, tantalum, tungsten alloy, plastic material loadedwith a radiopaque filler, and the like.

[0021] The choice for material composition may help provide filtercartridge 12 with a number of desirable characteristics. For example,material composition may provide filter cartridge 12 with desirablecharacteristics related to strength, flexibility, trackability,ovalization avoidance, coefficient of friction, axial compression, andthe like. In addition or as an alternative to material composition,filter cartridge 12 may vary in other ways to provide filter cartridge12 with desirable features and characteristics including those listedabove. For example, the flexibility of filter cartridge 12 may varyalong its length. This feature can be accomplished in a number ofdifferent manners, including changing the material composition oraltering the inside and/or outside diameters of filter cartridge 12.Additionally, filter cartridge 12 may be comprised of multiple layers ofmaterials and/or multiple sections or regions that are coupled.

[0022] In at least some embodiments, filter cartridge 12 may alsoinclude one or more notches 17 or other structural features that may,for example, provide filter cartridge 12 with desirable characteristicsincluding those listed above. For example, FIG. 1 depicts the one ormore notches 17 as defining a helical groove 19 formed in filtercartridge 12. Helical groove 19 can be formed in a number of ways. Forexample, groove 19 can be cut into filter cartridge 12 using known laseror other type of cutting or etching process. A number of other processescan be utilized to form groove 19. For example, filter cartridge 12 canbe molded (e.g., injection molded, etc.) in a manner that defines groove19. Alternatively, filter cartridge 12 may be comprised of a flattenedribbon that is wound into a shape that defines a tubular filtercartridge 12 having groove 19. It can be appreciated that groove 19 maybe defined in a number of additional ways without departing from thespirit of the invention.

[0023] The shape, arrangement, and configuration of groove 19 may alsovary. For example, groove 19 is illustrated in FIG. 1 as being anessentially regular helix extending along the length of cartridge 12. Insome embodiments, however, groove 19 may vary. For example, groove 19may extend along only portions of cartridge 12 or intermittently alongsections of cartridge 12. Additionally, the pitch of groove 19 may vary.For example, the pitch of groove 19 may be relatively wide or open atsome positions (e.g., near the proximal region of cartridge 12) andrelatively close at others (e.g., near the distal region of cartridge12). Moreover, the direction of groove 19 may vary. For example, groove19 may wind about cartridge 12 in a clockwise direction,counterclockwise direction, or combinations of directions.

[0024] It can be appreciated that groove 19 in filter cartridge 12 mayprovide device 10 with a number of desirable features. For example,groove 19 may increase the flexibility of cartridge 12. Additionally,groove 19 may increase the trackability of cartridge 12. Trackability isunderstood to be the ability of one device (e.g., cartridge 12) to“track” or advance over another (e.g., guidewire 16). According to thisembodiment, groove 19 may increase trackability, for example, by makingcartridge 12 more adaptable or more compliant so that it may more easilytrack over a device (i.e., guidewire 16) that may be significantlycontorted when positioned in the tortuous vasculature.

[0025] As stated above, some of the other components of device 10 mayinclude filter 14. Filter 14 may be adapted to operate between a firstgenerally collapsed configuration and a second generally expandedconfiguration for collecting debris in a body lumen. In someembodiments, filter 14 can be delivered to an appropriate intravascularlocation, for example “downstream” of an intravascular lesion, using anappropriate filter delivery and/or retrieval device 18. Similarly,filter 12 can be removed from the vasculature at the desired time withdevice 18 or another suitable device.

[0026] Filter 14 may include a filter frame 20 and a filter membrane orfabric 22 coupled to filter frame 20. Frame 20 may take the form of anyone of a number of appropriate shapes and configurations. For example,frame 20 may comprise a generally circular filter mouth or loop, whichmay defines the primary opening for blood to travel into and be filteredby filter 14. However, essentially any appropriate shape orconfiguration may be utilized without departing from the spirit of theinvention.

[0027] Frame 20 may be comprised of any appropriate material. Forexample, frame 20 may be comprised of a “self-expanding” shape-memorymaterial such as nickel-titanium alloy (to bias filter 14 to be in thesecond expanded configuration). Alternatively, frame 20 may be comprisedof essentially any appropriate metal, metal-alloy, polymer, combinationsthereof, and the like including any of the materials described herein.

[0028] Filter membrane 22 may be comprised of any appropriate materialsuch as a polymer and may be drilled (for example, formed by known lasertechniques) or otherwise include at least one opening 24. Holes oropenings 24 can be sized to allow blood flow therethrough but restrictflow of debris or emboli floating in the body lumen or cavity.

[0029] One or more struts 26 may extend between frame 20 and filtercartridge 12. In some embodiments, struts 26 can be coupled to filtercartridge 12 by a coupling 28, for example a heat-shrink tube, a crimpfitting, and the like. Alternatively, struts 26 may be coupled to filtercartridge 12 by one or more windings of struts 26 about filter cartridge12.

[0030] As stated above, at least some embodiments of device 10 includeguidewire 16, over which filter cartridge 12 may be slidably disposed.Guidewire 16 may include a distal stop 30. Distal stop 30 may define adistal-most position along guidewire 16 may be advanced to. In addition,guidewire 16 may also include a proximal stop 32. Stops 30/32 may bearranged so that filter cartridge 12 can be positioned between them. Adeployment sheath 34 may also be slidably disposed over guidewire 16.Sheath 34 may be used, for example, to help advance filter cartridge 12to the appropriate location along guidewire 16.

[0031] Although FIG. 1 illustrates filter cartridge 12 being slidablydisposed over guidewire 16, the invention is not intended to be limitedto use with only guidewires 16. It can be appreciated that the devicecould be any intravascular device or be any device designed to passthrough an opening or body lumen. For example, the device may comprise acatheter (e.g., therapeutic, diagnostic, or guide catheter), endoscopicdevice, laproscopic device, an embolic protection device, or any othersuitable device.

[0032] The use of filter cartridge 12 may include a number of steps. Forexample, filter cartridge 12 may be coupled to guidewire 16, for exampleby disposing cartridge between stops 30/32, by crimping cartridge 12onto guidewire 16, by using other suitable mechanical connections, or byany other suitable means. In some embodiments, cartridge 12 andguidewire 16 may be coupled before guidewire 16 is advanced through ablood vessel. Alternatively, guidewire 16 may be positioned in a bloodvessel and then cartridge 12 may be advanced over guidewire 16 to asuitable target location and filter 14 may be expanded. Advancingcartridge 12 over guidewire 16 may include the use of delivery sheath 18and the expansion of filter 14 may include advancing deployment sheath34 into contact or another suitable arrangement to expand filter 14.Sheath 18 and/or sheath 34 may be proximally retracted and anotherdiagnostic or therapeutic device (e.g., balloon catheter, atherectomycatheter, and the like) may be advanced over guidewire 16. The expandedfilter 14 may then be used to filter debris that may be generated by thetherapeutic device.

[0033]FIG. 2 is a perspective view of another example filter cartridge112. Cartridge 112 is similar to cartridge 12, expect that the one ormore notches 117 define a plurality of slots 119 within cartridge 112.Slots 119 may be formed according to any of the methods described hereinor any other appropriate process. The shape, arrangement, and number ofslots 119 may vary without departing from the spirit of the invention.For example, slots 119 may be generally rectangular in shape, square inshape, rounded in shape, or have any other appropriate shape.Additionally, slots 119 may be disposed at varying positions alongcartridge 112 and may vary in length so as to span, for example, about45 to about 320 degrees around the circumference of cartridge 112 ormore or less, depending the desired length. In some embodiments, abridge or other tying support (not shown) may be longitudinally disposedalong cartridge 112, for example along the inside surface, to helpmaintain the structural integrity of cartridge 112. This structuralfeature may be desirable when slots 119 span larger portions ofcartridge 112. Other variations for the configurations and arrangementsof slots 119 may include any of the variations attributed to any of thenotches and/or cartridges described herein.

[0034]FIG. 3 is a perspective view of another example filter cartridge212. Cartridge 212 is similar to the other cartridges disclosed herein,expect that it includes a series of fibers arranged in a braid 236.Braid 236 may be adapted and configured to provide cartridge 212 withdesirable flexibility and trackability characteristics including thosedescribed above. In some embodiments, braid 236 may be disposed on theoutside surface (as shown in FIG. 3) or the inside surface (not shown)of a support structure or tube 238. Alternatively, cartridge 212 may becomprised of braid 236 without the need for support tube 238. Accordingto this embodiment, cartridge may be manufactured, for example, bydisposing braid 238 on a mold or mandrel to define cartridge 212, andthen disassociating the defined filter cartridge 212 from the mold.

[0035] The arrangement and configuration of braid 236 may vary. Forexample, braid 236 may have a uniform or regular distribution alongcartridge 212. Alternatively, the pattern may be irregular orintermittent. The direction, closeness or tightness, and general shapemay also vary. Moreover, additional braids or layers may be disposed onbraid 236. For example, cartridge 212 may include a plurality of braids236 disposed on each other and may include other, non-braided layersdisposed therebetween.

[0036]FIG. 4 is a perspective view of another example filter cartridge312. Cartridge 312 is similar to other cartridges disclosed herein,except that it includes a coil 340. It can be appreciated that coil 340may provide cartridge 312 with desirable flexibility characteristics.For example, including coil 340 or a similar coiled structure mayincrease the flexibility of cartridge 312. Additionally, coil 340 mayenhance the trackability of filter cartridge 312. In some embodiments,coil 340 may comprise cartridge 312 thereby obviating the need for anysupport tube or structure. Other embodiments, however, may include asupport structure similar to support tube 238 illustrated in FIG. 3.

[0037]FIG. 5 is a perspective view of another example filter cartridge412. Cartridge 412 is similar to cartridge 312, except that a portion ofcoil 440 is “unwound” or otherwise configured to define filter frame 420of filter 414. According to this embodiment, cartridge 412 and filterframe 420 may be integral with one another or otherwise formed of thesame structure. This structural feature may be desirable for a number ofreasons. For example, cartridge 412 may cost less to manufacture bydecreasing the number of separate structural elements and by decreasingsome of the processing steps (e.g., attaching together separateelements).

[0038]FIG. 6 is an example mold or mandrel 542 that may be used in themanufacturing of filter cartridges, including those described herein andother embodiments. Mandrel 542 may include a base or base surface 544and may include one or more projections 546 extending therefrom. Mandrel542 may be comprised of any appropriate material, including thosedisclosed herein. In some embodiments, mandrel 542 may be comprised of awax or other soluble substance that can be readily dissolved followingthe molding procedure. This feature may be desirable by enhancing theability to release a newly molded filter cartridge from mandrel 542.

[0039] The shape, size, and arrangement of projections 546 may alsovary. In some embodiments, a plurality of rounded projections 546 may beessentially uniformly distributed throughout mandrel 542. Alternatively,projections 546 may have a square or other shape and may be irregularlydistributed. Additionally, a variety of shapes, sizes, and distributionsmay be utilized along mandrel 542.

[0040] Molding of a filter cartridge with mandrel 542 may include any ofa number of known molding techniques. For example, manufacturing mayinclude dip molding, spray molding, injection molding, and the like.These manufacturing techniques may generally include disposing a filtercartridge material (not shown) adjacent mandrel 542 so as to define afilter cartridge. The newly defined cartridge may be disassociated frommandrel 542 and the flexibility thereof may be altered. For example, theflexibility may be altered by forming one or more notches or slotstherein, by forming a spiral groove therein, etc. as described above.Other manufacturing steps may include coupling a filter, for examplefilter 14, to the newly molded filter cartridge.

[0041] FIGS. 7 sectional and 8 illustrate cross-sectional views ofmandrel 542 where example filter cartridges have been molded thereon.For example, FIG. 7 illustrates filter cartridge 512 molded on mandrel542. According to this embodiment, the shape of cartridge 512 mayinclude a plurality of projections 548 a/b along both its inside surface550 and its outside surface 552, respectively, that generally conform tothe shape of mandrel 542. In some other embodiments, an alternativefilter cartridge 612 may be molded as shown in FIG. 8. Cartridge 612 maybe configured or otherwise thickened so that projections are 648 a maybe seen on inside surface 650, but not on outside surface 652.

[0042] Another example mandrel 742 is illustrated in FIG. 9. Mandrel 742is essentially the same in form and function as mandrel 542, except thatit includes one or more dimples 746 extending inward from a base member744. Mandrel 742 may be used to mold filter cartridges in a mannersimilar to what is described above. For example, molding a filtercartridge using mandrel 742 may result in a filter cartridge withdimples similar to dimples 746.

[0043] It should be understood that this disclosure is, in manyrespects, only illustrative. Changes may be made in details,particularly in matters of shape, size, and arrangement of steps withoutexceeding the scope of the invention. The invention's scope is, ofcourse, defined in the language in which the appended claims areexpressed.

What is claimed is:
 1. A medical device, comprising: an elongate shafthaving a proximal region and a distal region; the shaft including one ormore stops coupled adjacent the distal region; a tubular cartridgeslidably disposed over the shaft; the tubular cartridge including one ormore notches defined therein; and a filter coupled to the cartridge. 2.The medical device of claim 1, wherein the shaft is a guidewire.
 3. Themedical device of claim 2, wherein the guidewire includes one or morestops coupled thereto.
 4. The medical device of claim 1, wherein tubularcartridge comprises a polymer.
 5. The medical device of claim 1, whereinthe one or more notches include a spiral groove cut in the tubularcartridge.
 6. The medical device of claim 1, further comprising adeployment sheath slidably disposed over the shaft.
 7. The medicaldevice of claim 6, further comprising a delivery sheath slidablydisposed over the shaft.
 8. An embolic protection filtering device,comprising: an elongate guidewire; a tubular filter cartridge slidablydisposed over the guidewire, the cartridge having a length and aspiraling groove defined along at least a portion of the length; and anembolic protection filter coupled to the filter cartridge.
 9. Thefiltering device of claim 8, wherein the tubular filter cartridgecomprises a polymer.
 10. The filtering device of claim 8, whereintubular filter cartridge includes a proximal region and a distal region,and wherein the distal region is more flexible than the proximal region.11. An embolic protection filtering device, comprising: an elongateguidewire; a tubular filter cartridge slidably disposed over theguidewire, the cartridge having a length and including a coil disposedalong at least a portion of the length; and an embolic protection filtercoupled to the filter cartridge.
 12. The filtering device of claim 11,wherein the guidewire includes one or more stops coupled thereto. 13.The filtering device of claim 11, wherein the filter cartridge comprisespolymer.
 14. The filtering device of claim 11, wherein the filtercartridge comprises a metal.
 15. The filtering device of claim 11,wherein the filter includes a filter frame, and wherein the filter frameis defined by a portion of the coil.
 16. An embolic protection filteringdevice, comprising: an elongate shaft a filter cartridge slidablydisposed over the shaft; a filter coupled to the filter cartridge; andmeans for increasing the flexibility of the filter cartridge.
 17. Amethod of manufacturing an embolic protection filtering device,comprising the steps of: providing a mandrel having an outer surface;disposing a filter cartridge material on the outer surface of themandrel to define a filter cartridge; altering the flexibility of thefilter cartridge; and coupling a filter to the filter cartridge.
 18. Themethod of claim 17, wherein outer surface of the mandrel includes aplurality of projections, and wherein the step of disposing a filtercartridge material on the outer surface of the mandrel to define afilter cartridge includes defining a filter cartridge with a pluralityof projections.
 19. The method of claim 17, wherein outer surface of themandrel includes a plurality of dimples, and wherein the step ofdisposing a filter cartridge material on the outer surface of themandrel to define a filter cartridge includes defining a filtercartridge with a plurality of dimples.
 20. The method of claim 17,wherein the step of disposing a filter cartridge material on the outersurface of the mandrel to define a filter cartridge includes spraymolding the filter cartridge material onto the mandrel.
 21. The methodof claim 17, wherein the step of disposing a filter cartridge materialon the outer surface of the mandrel to define a filter cartridgeincludes dip molding the mandrel into the filter cartridge material. 22.The method of claim 17, wherein the step of altering the flexibility ofthe filter cartridge includes forming a spiral groove in the filtercartridge.
 23. The method of claim 17, wherein the step of altering theflexibility of the filter cartridge include forming one or more slots inthe filter cartridge.
 24. A method of filtering embolic debris,comprising the steps of: providing a guidewire; providing a tubularfilter cartridge having a filter coupled thereto, the filter cartridgeincluding one or more notches defined therein to enhance the flexibilityof the cartridge; coupling the filter cartridge to the guidewire;advancing the guidewire through a blood vessel to a target location;expanding the filter; advancing a therapeutic device over the guidewire;and filtering debris generated by the therapeutic device with theexpanded filter.
 25. The method of claim 24, wherein the step ofcoupling the filter cartridge to the guidewire precedes the step ofadvancing the guidewire through a blood vessel to a target location. 26.The method of claim 24, wherein the step of coupling the filtercartridge to the guidewire follows the step of advancing the guidewirethrough a blood vessel to a target location.
 27. The method of claim 24,wherein the step of coupling the filter cartridge to the guidewireincludes sliding the filter cartridge over the guidewire to a suitableposition and mechanically attaching the cartridge to the guidewire. 28.The method of claim 24, wherein the step of coupling the filtercartridge to the guidewire includes sliding the filter cartridge overthe guidewire to a position between two stops disposed on the guidewire.